This present invention is generally in the field of medical diagnosis, and more particularly it is concerned with a device and method for diagnosing otitis media.
Otitis media (inflammation of the middle ear) is amongst the most frequent primary diagnosis at visits to physicians by children younger than 15 years, in the US, as reported by the American Academy of Pediatrics in the Pediatric Guidelines, Volume 94, Number 5, November 1994. In a paper entitled xe2x80x9cOtitis Media in Childrenxe2x80x9d, S. Berman M. D., New England Journal of Medicine, Jun. 8, 1995, Vol. 332, No. 23, pp. 1560-1565, it is stated that approximately 17% of children under the age of three will have had three episodes of Otitis media within he past six months.
Otitis media is caused by bacteria or viruses (at times both) that enter the nose or throat and ascend the eustachian tube to reach the middle ear. This occurs when the Eustachian tube does not function properly, often because it is inflamed from a cold, sinus or throat infection, an allergy attack or owing to some other physiological disorder. Otitis media causes earache, a red inflamed eardrum (referred to interchangeably also as tympanic membrane), a build up of pus and mucus behind the eardrum, resulting at times in temporary hearing loss. These symptoms may all be present, or only some of which, and at different extent of appearance.
These clinical symptoms and physical signs may partially or all be present and with varying degrees of severity.
The disease is responsible for considerable morbidity, apprehension and suffering and results in extensive periods of absenteeism from work by the family.
Otitis media is the most common reason for the administration of antibiotics in childhood. It is the standard practice to prescribe antibiotics when a medical practitioner suspects otitis media.
Research on the etiology of the infection has shown that bacteria may be isolated following paracentesis of the tympanic membrane (penetration of the eardrum) in 50% of the patients. This is the basis for the widespread use of antibiotics. In a considerable number of instances, recovery is incomplete and the fluid remains within the middle ear cavity and is an ideal reservoir for re-infection (this is known as otitis media with effusion-OME). Inrecent years, the more extensive use of antibiotics has resulted in resistance of the organisms to the usual first line of therapy; as a result more extensive use of expensive broad-spectrum antibiotics has become common practice. This not only adds to the financial burden of treatment of the disease, but is also a crucial factor in promoting the further emergence of resistant bacterial strains.
The medical practitioner primarily makes the diagnosis after obtaining an appropriate history and direct examination with an otoscope, of the tympanic membrane. The membrane is translucent and normally it reflects the light""source so that a light reflex is seen. At the time of infection, there are varying degrees of redness, lack of luster and varying degrees of yellow discoloration with bulging of the tympanic membrane. All these findings indirectly reflect on the extent of the inflammation behind the tympanic membrane, that is inflammation within the middle ear.
However, the visual examination by an otoscope is often difficult to perform because of a restless patient (in particular toddlers and young children) and blocking of the external auditory canal by varying degrees of wax, resulting in poor visibility of the tympanic membrane. Furthermore, interpretation of the visual findings is dependent on the subjective assessment of the examining physician. There is therefore a distinct need for a non-invasive method to reliably diagnose the disease and quantify the extent of the inflammation.
Other examinations which are at times performed, mainly in reoccurring events, for providing the physician with information that is not learned through visual observation alone, are audiograms (hearing tests), tympanometry (measuring compliance of the tympanic membrane), pneumatic otoscopy (to assess the mobility of the tympanic membrane), blood tests to determine whether the inflammation is bacterial or viral, etc. however, these examinations are time consuming, require special facilities, expertise and laboratory equipment, all of which are expensive and unpleasant for the patient.
It is most likely that a viral disease will have lesser inflammation as opposed to a bacterial disease. Follow-up examinations which allow a quantitative assessment to be performed at each examination would be of great value in obtaining objective information as to the response to treatment and recovery of the inflammation. Therefore it would be desirable to provide a device and a method which would reliably result in a more accurate diagnosis, thus allowing the prescription of appropriate therapy and allow the correct follow up in the instance of bacterial inflation. This approach would provide the means for deciding on appropriate treatment and not the inappropriate use of antibiotic therapy. In addition to facilitating more correct clinical practice there is no question tat such a device would be more cost effective.
It will be noted that it is not an object of the present invention to measure or monitor the core temperature or the ear temperature of the patient, as known per se. Such devices are broadly disclosed, for example in U.S. Pat. No. 5,653,239.
It is thus one aspect of the present invention to provide a novel approach for diagnosis of otitis media with a method that is rapid, non-invasive and essentially pain-free. Another aspect of the invention is concerned with a diagnostic device for diagnosis of otitis media.
The device and method according to the present invention will not only detect the ailment, but will also assist in determining the extent of its severity and will enable simple and relative accurate follow-up.
According to a fist of its aspects the present invention is concerned with a diagnostic device for diagnosing an inflammatory process at an individual""s middle ear, the device comprising a thermally isolated ear piece having a rear end and a front end; an energy receiving element fitted at the front end for heat pickup at a portion of the auditory canal in close proximity with the tympanic membrane; wherein the energy receiving element is inserted into the individual""s ear at a reference temperature which is lower than the individual""s core temperature; an indicator associated with the energy receiving element for indicating change in temperature with respect to time.
As it will become apparent hereinafter, the device may be carried out in many different embodiments and may have many forms. Setting as an example, the device may be disposable, portable-hand held or stationary.
According to a particular, preferred embodiment the energy receiving element is heat conductively connected to a sensor element extending in a direction towards said rear end. The sensor element according to this embodiment has to be at a known temperature bellow the core temperature. Typically the energy receiving element is integrally fitted at a front end of a thermally conductive sensor element extending through the ear piece towards the rear end; and where said indicator is associated with the energy receiving element.
According to one embodiment of the invention, a predetermined period of time is measured by a chemical reaction wherein upon initializing a reaction, a distinct indication appears after said predetermined period of time. One particular example is a chemical reaction involving mixing two chemical compounds with one another, whereby the indication appears after said predetermined period of time. Another example is a chemical reaction involving exposing a light sensitive agent to light or a gas sensitive agent to gas (such as oxygen contained in the air), whereby the indication appears after said predetermined period of time.
According to one embodiment the predetermined time measuring arrangement is integral with a rear portion of the device.
The indicator is adapted for generating distinctive visible or audible diagnostic signals indicating at least an inflamed condition and a non-inflamed condition. According to one example, the indicator is a substance changing its color in reaction to temperature change. This application is suitable in particular for use with disposable devices, although not limited thereto. The indicator may also be an LCD display, one or more LEDs, etc.
The indication may indicate a particular state e.g., non-inflamed, viral or bacterial inflammation. Alternatively, the indicator may provide a continuous indication by means of a scale, gradual change of color, etc. An audible signal may be generated, in addition to a visible signal, or alone. Even more so, the device and method of the invention provide a reliable aid for establishing whether a prescribed antibiotic course has succeeded.
According to one embodiment the energy receiving element and the indicator are in the form of a thermometer. By a different embodiment the energy receiving element is in the form of a thermometer and the indicator may be an LCD display.
According to a preferred design of the device the energy receiving element is of known conductive geometry where only a front portion thereof is engageable with the auditory canal. Typically the energy receiving element has a tip with a shape selected out of one of a flat, concave, convex and a spheric section.
According to still another embodiment of the invention, the ear piece is formed with a bore for visualizing the auditory canal and the tympanic membrane (as an otoscope). For that purpose it is advantageous that a light source be provided at or adjacent the rear end, for illumination of the tympanic membrane. Such a device may also be fitted with optic fibers, transferring light from a light source to the front end or an image from the front end to a visualizing element.
According to another preferred embodiment of the invention, the energy receiving element is integrally formed at an end of thermally conductive sensor element extending through the ear piece; said sensor element comprising at least one temperature transducer for measuring temperature and emitting a temperature responsive signal; the device further comprising a microcontroller for recording said signal at pre determined intervals of time and for calculating the rate of heat transfer in a direction from the energy receiving element towards the at least one temperature transducer.
Typically there are three or more temperature transducers spaced along the sensor element; each of which being connected to the micro-controller. The one or more sensor element preferably coaxially extends through the ear piece. In case the sensor element is made tubular (for visualization therethrough), the at least one temperature transducer may be annular.
Still preferably, the ear piece is fitted with a replaceable sheath conforming with the shape and size of the individual""s auditory canal.
The reference temperature may be set by a peltier element associated with the device or with a heat exchanger formed with a receptacle for receiving at least a portion of the device. Such arrangements may be integral with the device or detachably connectable.
By a second of its aspects, the present invention is directed to a diagnostic method for diagnosing an inflammatory process at an individual""s middle ear by determining the quantity of heat energy extracted over a predetermined period of time from the auditory canal, at a vicinity in close proximity with the tympanic membrane.
The method comprises the following steps:
(a) Cooling a heat sensing device to a reference temperature bellow the individual""s core temperature;
(b) Inserting the heat sensing device into the auditory canal in close proximity with the tympanic membrane;
(c) Measuring the temperature sensed by the heat sensing device at predetermined intervals of time and coordinates;
(d) Calculating the rate of temperature change over a given period of time and generating a diagnostic signal indicative of the inflammatory state of the ear.
The reference temperature is typically in the range of between about 10 to 36xc2x0 C.
For easing the insertion of the device into the individual""s ear and to improve thermal conductivity, prior to step (b) a heat conductive liquid or gel-like material is applied on the temperature sensing device. The liquid material is preferably an oily substance and may comprise some therapeutic agent.
Preferably, the quantity of heat energy is measured by a device comprising a thermally isolated ear piece having a rear end and a front end; an energy receiving element fitted at the front end for heat pickup at a portion of the auditory canal in close proximity with the tympanic membrane; wherein the energy receiving element is inserted into the individual""s ear at a reference temperature which is lower than the individual""s core temperature; an indicator associated with the energy receiving element for indicating change in temperature with respect to time.
Although it is not an object of the invention to measure or monitor the core temperature or the ear temperature of the patient, it will be appreciated t these parameters may be measured by the device of the invention or may be incorporated therewith, for practical reasons.